shift = int(input())
text = input()
# 转换为小写，以便处理
text = text.lower()
cipher_text = ""

# 遍历文本中的每个字符
for char in text:
    if char.isalpha():  # 检查字符是否为字母
        # 计算偏移后的字符
        new_char = chr((ord(char) - ord('a') + shift) % 26 + ord('a'))
        cipher_text += new_char
    else:
        # 非字母字符保持不变
        cipher_text += char

print(cipher_text)
